Urpf; No-Exits The Configuration Session Without; Committing The Configuration Changes; Cancel-Remains In The Configuration Mode - Cisco ASR 9000 Series Configuration Manual

uRPF

Command or Action
Step 6
ipsubscriber ipv4 l2-connected
Example:
RP/0/RSP0/CPU0:router(config-if)# ipsubscriber ipv4
l2-connected
Step 7 initiator dhcp
Example:
RP/0/RSP0/CPU0:router(config-if)# initiator dhcp
Step 8
Use the commit or end command.
Establishing Subscriber Session on Ambiguous VLANs: An example
configure
interface Bundle-Ether100.10
encapsulation ambiguous dot1q 14 second-dot1q any
ipv4 address 2.1.12.12 55.255.255.0
service-policy type control subscriber PL1
ipsubscriber ipv4 l2-connected
!
!
end
uRPF
Unicast Reverse Path Forwarding (uRPF) is a feature in BNG that verifies whether the packets that are received
on a subscriber interface are sent from a valid subscriber. uRPF only applies to subscribers using an L3 service.
For PPPoE subscribers, the uRPF check ensures that the source address in the arriving packet matches the set
of addresses associated with the subscriber. The subscriber addresses are the IPCP assigned addresses, or any
framed routed assigned through RADIUS. PPPoE subscribers are identified by session ID and VLAN keys.
BNG performs the uRPF check to ensure that the source IP address in the arriving packets matches the expected
session IDs and VLAN keys.
For IPoE subscribers, the subscriber addresses are the ones assigned through DHCP. IPoE subscribers are
identified by the incoming MAC address. The uRPF check ensures that the source IP address is the one
allocated by DHCP to the source MAC address.
Cisco ASR 9000 Series Aggregation Services Router Broadband Network Gateway Configuration Guide,
Release 4.3.x
234
Configuring Subscriber Features
Purpose
Enables l2-connected IPv4 IP subscriber.
Enables initiator DHCP on the IP subscriber.
commit—Saves the configuration changes and remains
within the configuration session.
end—Prompts user to take one of these actions:
• Yes— Saves configuration changes and exits the
configuration session.
• No—Exits the configuration session without

committing the configuration changes.

• Cancel—Remains in the configuration mode,

without committing the configuration changes.

OL-28375-03